The Foundation: Holds a Home in Place
A foundation holds a house above ground, prevents it from moving along with the earth it sits in, and helps protect against both cold and moisture. A foundation’s structure varies depending on when a home was built, the climate in which the home was built, and whether or not the home was built with a basement or atop a crawl space. The appearance and nature of cracks in a foundation can foreshadow water leaks, structural issues and vulnerability in the event of an earthquake or other natural disaster. Often, cracks and unevenness are due to “settling.” Settling can be minor or more dramatic. It happens over time to almost all structures.
During your home inspection, an inspector will determine which type of foundation your home has and examine it for potential defects. Foundation inspections involve both a review of the home’s interior, usually focusing on the basement or crawl space, as well as its exterior, where foundation cracks and shifts are often apparent. According to data in This Old House, the average U.S. house weighs 50 tons and the average foundation weighs 7.5 tons; when it comes to new construction, foundations may account for eight to 15 percent of the total cost of a new construction project. These are figures worth keeping in mind if you’re evaluating a home with foundation issues.
Older homes may be built with stone, mortar or brick foundations, all of which may be prone to leaks and cracks over time. However, most homes built in the latter half of the twentieth century are constructed on foundations made from a combination of concrete and steel reinforcements, which are built in several different ways. Poured concrete foundations are typically reinforced with steel and considered favorable. Concrete slab foundations consist of a flat piece of poured concrete; slab foundations are difficult to inspect because much of the foundation is hidden, and they can also be more conducive to insect infestation. Cement block foundations (built from “concrete masonry units”) often occur in homes with basements, but even the smallest of horizontal cracks in such foundations can be a sign of repairs to come.
Brick foundations occur mostly in older homes and are prone to seepage, settling and crumbling or aging of bricks. Stone foundations are also common in older homes and they are prone to settling and seepage.
Regardless of the type of foundation your home is built on, there are several key signs inspectors look for in determining a foundation’s condition. Foundation damage, in its earliest stages, tends to manifest itself in the form of cracks or heaving, moisture pooling or moisture penetrating hairline cracks which have begun to appear in walls. In the most severe cases, a home’s walls may begin to slant or buckle, especially around the corners, and the floor may begin to drop; mud or clay may also begin to seep into the basement.
Some foundation settling or damage may be inevitable, particularly in an older home, but an inspector can help you determine the degree of danger or needed repairs to the home. Depending on the type of foundation your home has, sealants and reinforcements may be able to combat any early signs of trouble for many years to come.